Fathi AbdelMalek

A Novel Birefrigent Photonic Crystal Fiber Surface Plasmon Resonance Biosensor

A numerical analysis of a novel birefringent photonic crystal fiber (PCF) biosensor constructed on the surface plasmon resonance (SPR) model is presented in this paper. This biosensor configuration utilizes circular air holes to introduce birefringence into the structure. This PCF biosensor model shows promise in the area of multiple detection using HE^x₁₁ and HE^y₁₁ modes to sense more than one analyte. A numerical study of the biosensor is performed in two interrogation modes: amplitude and wavelength. Sensor resolution values with spectral interrogation yielded 5 × 10^-5 RIU (refractive index units) for HE^x₁₁ modes and 6 × 10^-5 RIU for HE^y₁₁ modes, whereas 3 × 10^-5 RIU for HE^x₁₁ modes and 4 × 10^-5 RIU for HE^y₁₁ modes are demonstrated for the amplitude interrogation.

Bending Effects on Highly Birefringent Photonic Crystal Fibers With Low Chromatic Dispersion and Low Confinement Losses

Photonic crystal fibers (PCFs) with elliptical air-holes located in the core area that exhibit high birefringence, low losses, enhanced effective mode area, and low chromatic dispersion across a wide wavelength range have been presented. The effects of bending on birefringence, confinement losses and chromatic dispersion of the fundamental mode of the proposed PCFs have been thoroughly investigated by employing the full vectorial finite element method (FEM). Additionally, localization of higher order modes is presented. Also, effects of angular orientation on bending loss have been reported. Significant improvement on key propagation characteristics of the proposed PCFs are demonstrated by carefully altering the desired air hole diameters and their geometries and the hole-to-hole spacing.

Enhanced Effective Area Photonic Crystal Fiber With Novel Air Hole Design

There is interest in photonic crystal fibers (PCFs) that possess a large effective area. We demonstrate that it is possible to design a PCF structure configuration with an effective mode area as high as 3000 μm2. The proposed PCF structures consist of five air-hole rings, where the air hole diameters are different from one ring to another. In the second ring six air holes are alternatively removed. The effective mode area of the proposed structure was calculated and compared with effective mode areas reported in literature. It is shown that the effective mode area is enhanced compared to other structures. Additionally, critical propagation properties such as chromatic dispersion, confinement losses, bend losses and nonlinear coefficient of proposed PCF structures are reported thoroughly.

An Endlessly Single-Mode Photonic Crystal Fiber With Low Chromatic Dispersion, and Bend and Rotational Insensitivity

A single-mode photonic crystal fiber (PCF) with low chromatic dispersion, low bend, and rotational sensitivity is presented. The transverse electric field vector distributions of the fundamental, higher order and fundamental space filling modes, their effective indices, chromatic dispersion, confinement, bending and rotational losses are reported using full-vector finite-element method (FEM). In addition, the endlessly single mode behavior is demonstrated by employing the V parameter of the proposed PCF. It has also been shown that the proposed PCF design is insensitive to bends and rotations.

Realization of a High Coupling Efficiency by Employing a Concave Lens Based on Two-Dimensional Photonic Crystals With a Negative Refractive Index

A study of the interaction of a continuous-wave Gaussian beam with a concave lens used as a spot-size converter (SSC) is presented. The lens is based on a 2-D photonic crystal (PC) structure with a negative refractive index. A numerical method based on a 2-D finite-difference time domain was employed to investigate the light propagation in a photonic integrated circuitry (PIC). The PIC consisted of a single-mode fiber, an SSC, and a PC waveguide (PCW). By employing an optimized planoconcave lens, a large spot-size area of the Gaussian beam was focused/transformed into a very small spot-size area, which is even smaller than the order of the operating wavelength. Optimization of the proposed device parameters has also been reported. A significant reduction in the device size, transmission efficiency, and coupling efficiency has been achieved by optimizing the planoconcave lens and the PCW.

Optimization of compact lateral, vertical, and combined tapered spot-size converters by use of the beam-propagation method

A study of lateral, vertical, and combined spot-size converters is presented that employs full-vectorial numerical techniques such as modal solution and beam propagation based on the finite-element method. Spot-size expansion, coupling efficiency to an optical fiber, the mode-beating phenomenon, and transmission losses are demonstrated for all three spot-size-converter designs. Optimization of the device fabrication parameters is also reported. A significant improvement in the coupling efficiency and reduction of the device length are achieved when the length and the width are changed simultaneously.

Nanophotonic Sensor Based on Photonic Crystal Structure Using Negative Refraction for Effective Light Coupling

In this paper, using the 2-D finite-difference time-domain (FDTD) method, we study a novel biosensor based on collimation effects in photonic crystals (PCs) with negative refractive index. Coupling the collimated beam to a line of air holes (sensing region) filled with normal air, dry air, liquid, and gas is thoroughly investigated. It is shown that by an appropriate selection of design parameters, such as, the air cylinder radii and coupling distance, it is possible to achieve ultracompact sensing platforms. The collimation effect features channel allocation in nanosystems and high sensitivity for biomolecules sensing applications.

Photonic Crystal Fiber With an Ultrahigh Birefringence and Flattened Dispersion by Using Genetic Algorithms

We developed a high-throughput technique to design photonic crystal fiber (PCF) structures with desired properties and functionalities. By using a genetic algorithm, a high birefringence and an ultra-flattened chromatic dispersion over a large wavelength range are achieved. It is shown that a low confinement loss can be obtained while the birefringence remains the same. The numerical results show that the presented PCF structure can be successfully employed as maintaining polarization devices working in a large zero- chromatic dispersion region.

A Novel Design of Photonic Crystal Lens Based on Negative Refractive Index

In this study a concave lens based on two dimensional photonic crystal platform with negative refractive index is presented. The proposed lens is employed as a spot-size con- verter to facilitate coupling of the light from a single mode flbre with a large spot-size area into photonic crystal waveguide with a very small spot-size area, even smaller than the operating wavelength. Optimisation of the lens and its integration with the single mode flbre and photonic crystal waveguide into a single optical chip was performed by employing 2D Finite-Difierence Time-Domain (FDTD). A signiflcant reduction of the optical chip dimensions and high cou- pling e-ciency have been achieved by optimizing each device (the lens and the photonic crystal waveguide).

Design of Multicavities on Left-Handed Photonic-Crystal-Based Chemical Sensors

This paper presents a theoretical study on a novel chemical sensor platform based on a 2-D photonic crystal with negative refraction (PCNR). The proposed device consists of distributed multinanocavities embedded within the PCNR. A 2-D finite-difference time-domain method with perfectly matched layers has been employed to investigate the performance of the sensor for different analytes and structural parameters. The calculations show that it is possible to detect simultaneously two analytes when the refractive index is larger than that of water. The quality factor was determined to be around 105 when the radii of the central nanocavity is and that of the external is .